The present invention relates to a lock, in particular a lock for locking a motor-vehicle steering column, said lock being fitted with a locking element which is displaceable to-and-fro between a locked and an unlocked position, and with a control element that can be rotated to-and-fro by a drive to axially displace said locking element or a drive element cooperating with the locking element in either direction, said control element enclosing the locking element or its drive element and furthermore:
(a) being fitted with two inner bevels or two inner helical grooves that cooperate with two protrusions which extend radially and mutually diametrically opposite with respect to the control element""s axis of rotation and which are part of the locking element or its drive element, said bevels or grooves each merging at the end that corresponds to the unlocked position of the locking element into an end face located in a plane extending perpendicular to the axis of rotation of the control element, or
(b) comprising an inside thread that cooperates with a protrusion of the locking element or its drive element which extends radially relative to the axis of rotation of the control element and said inside thread merging at the end corresponding with the locking element""s unlocked position into an end face located in a plane extending perpendicular to the control element""s axis of rotation.
The state of the art includes a lock, in particular for locking a motor vehicle steering column, which is fitted with a locking element displaceable to-and-fro between a locked and an unlocked position and furthermore with a control element rotatable to-and-fro by a drive for axially displacing in either direction the locking element or a drive element cooperating with the locking element, wherein special measures are taken in order to assure that the locking element each time moves precisely into the locked or the unlocked position, but no farther, even if the control element should continue rotating, that is, even if the drive does not stop at once when the locking element has reached the locked or the unlocked position. For that purpose the locking element or its drive element and the control element are arranged coaxially, and the locking element or its drive element and the control element cooperate by means of:
two radial protrusions which are configured diametrically opposite each other relative to the control element""s axis of rotation and which each are spring loaded and displaceable in a direction perpendicular to the control element""s axis of rotation, and
two bevels as well as two end faces located in a common plane which extends perpendicular to the control element""s axis of rotation, each of said end faces adjoining a respective bevel and extending as far as beside the other bevel,
in a manner such that the inner locking element or its inner drive element, upon rotation of the outer control element in that direction in which the protrusions run on the bevels to the end faces, is axially displaced correspondingly and stops moving when the protrusions pass from the bevels onto the end faces and remains in such axial position until the control element is rotated in the opposite direction, whereupon the protrusions run on the bevels away from the end faces, with the locking element or its drive element moving axially in the opposite direction. The protrusions may be provided on the locking element or its drive element, the bevels and the end faces may be provided on the control element and the protrusions may be in the form of two pins located in a common transverse borehole of the locking element or its drive element and loaded by a common helical compression spring (DE 44 36 326 C1).
Moreover, a lock already has been proposed, in particular to lock a motor-vehicle steering column, which is fitted with a locking element displaceable to-and-fro between a locked and an unlocked position, and further with a control element that is rotatable to-and-fro by means of a drive to axially displace the locking element or a drive element cooperating with the locking element in either direction, the control element enclosing the locking element or its drive element and comprising two inner bevels cooperating with two radial protrusions of the locking element or of its drive element which are diametrically opposed to each other relative to the control element""s axis of rotation, each bevel merging at each end into an end face located in a plane extending perpendicular to the axis of rotation of the control element, wherein:
one bevel of the control element and its two end faces are offset in the direction of the control element""s axis of rotation relative to the other control element""s bevel and its two end faces, and the one bevel and its two end faces are located at a greater distance from the control element""s axis of rotation than the other bevel and its two end faces, and
the two protrusions of the locking element or of its drive element are mounted in a stationary manner, such that the protrusion with which the control element""s bevel that is farther from the control element""s axis of rotation cooperates and with which its two end faces cooperate is offset by a corresponding distance in the direction of the axis of rotation of the control element relative to that protrusion with which the other bevel of the control element and its two end faces cooperate and is correspondingly longer.
The control element may be provided at the end of each end face remote from the associated bevel with a stop surface for that protrusion of the locking element or its drive element with which the end face cooperates. The protrusions of the locking element or its drive element each may consist of a pin force-fitted in a borehole of the locking element or its drive element (DE 101 09 609.7).
A further lock already has been proposed, particularly for locking a motor-vehicle steering column, which is fitted with a locking element displaceable to-and-fro between a locked and an unlocked position and further comprising a control element rotatble to-and-fro by a drive for axially moving the locking element or a drive element cooperating with it in either direction, the locking element or its drive element and the control element being arranged coaxially and cooperating by means of:
a cross-pin resting in an axially displaceable manner in a cross-borehole of the inner locking element or its inner drive element, and
two helical inner grooves and a planar end face of the outer control element, said end face extending perpendicularly to the control element""s axis of rotation and adjoining the two grooves, and being bounded by a sidewall running from the bottom of one groove at a distance past the other groove along the outer side thereof to the locking element or its drive element,
in such a way that the locking element or its drive element upon rotation of the control element in that direction where the two cross-pin ends projecting from the cross-borehole of the locking element or its drive element run in the grooves to the control element""s end face is correspondingly displaced axially in order that when the cross-pin ends pass from the grooves onto the end face, the locking element or its drive element remains stationary and remains in this axial position until the control element is rotated in the opposite direction and the cross-pin ends move inside the grooves away from the end face, so that the locking element or its drive element moves axially in the opposite direction. The control element""s grooves may merge at the ends located away from the first end face into a second control element""s end face which extends perpendicularly to the control element""s axis of rotation and is bounded by a sidewall running from the bottom of one groove at a distance from the other groove and past it along its outer side to the locking element or its drive element, as a result of which, the locking element or its drive element, when the control element is rotated in that direction in which the two ends of the cross-pin projecting from the cross-borehole of the locking element or its drive element run in the grooves from the first end face to the second end face of the control element, after the corresponding axial displacement of the locking element or its drive element, when the cross-pin ends pass from the grooves onto the second end face, stops moving and remains in this axial position until the control element is rotated in the opposite direction, whereupon the cross-pin ends run in the grooves from the second end face to the first end face, so that the locking element or its drive element is axially displaced in the opposite direction (German Patent No. 100 30 680 granted Oct. 18, 2001 or U.S. Pat. No. 6,543,262 issued Apr. 8, 2003).
Lastly a lock is known particularly for locking a motor-vehicle steering column which comprises a locking element displaceable to-and-fro between a locked and an unlocked position, and further a control element rotatable to-and-fro by a drive to axially displace the locking element in either direction, the control element enclosing the locking element and being fitted with an inside thread which cooperates with a locking-element""s protrusion extending radially relative to the axis of rotation of the control element and which inside thread merges at each of its two ends into an end face situated in a plane extending perpendicular to the control element""s axis of rotation. The locking element""s protrusion is in the form of a cross-pin displaceable axially in a cross-borehole of the locking element. Each end face of the control element""s inside thread is bounded by a sidewall configured in such a way that after the cross-pins transition onto the end face due to the control element""s rotation in the corresponding direction, the cross-pin remains on this end face, even if the control element is further rotated in the same direction, and leaves this end face and enters the inside thread by an end projecting from the locking element only when the control element is rotated in the opposite direction (German Patent No. 199 61 975 granted Dec. 14, 2000 or U.S. Published Patent Application No. US2001/0025516A1 published Oct. 24, 2001.
The objective of the present invention is to create a lock of the kind discussed at the beginning, the operation of which is furthermore improved.